The present invention is directed to improved devices and methods for reducing infection associated with the collection of body fluid from a human or animal subject and the introduction of fluids into the body.
In modern medical practice it is often desirable either to drain fluids from or to introduce fluids into a human or animal subject under sterile conditions. For example, it is a routine practice to catheterize hospital patients for urinary or closed wound drainage. Similarly, a number of body cavities, such as the urinary bladder and the peritoneal cavity, for example, are routinely irrigated during treatment of various disorders. In these and other, similar situations the continued sterility of all associated devices used for passing fluid to and from the body may be critically important, for a contaminated device will in many cases lead to infection of the patient.
It is well recognized that conventional drainage devices are a prime source of infection in catheterized patients. For example, in the area of bladder drainage, a large proportion of catheterized patients suffer from urinary tract infections attributable to contaminated drainage devices. In many cases, the drainage collection device itself becomes contaminated in use and infection then ascends in a retrograde manner from the drainage collection device to the patient via the drainage catheter. Such retrograde infection from a contaminated drainage or infusion device has been observed in patients undergoing urinary, wound, biliary, gastro-intestinal drainage, peritoneal dialysis, and hyperalimentation treatment for example. See, e.g., E. M. Goldberg, et al., "Peritoneal Dialysis", Dialysis and Transplantation, 1975, 4:50; J. H. Isaacs, et al., "Foley Catheter Drainage Systems and Bladder Damage", Surgery, Gynecology & Obstetrics, May 1971, p. 889; R. E. Desautels, "The Causes of Catheter-Induced Urinary Infections and Their Prevention", J. Urology, 1969, 101: 757; R. E. Desautels, et al., "Technical Advances in the Prevention of Urinary Tract Infection", J. Urology, 1962, 87: 487; R. E. Desautels, "Aseptic Management of Catheter Drainage", New Eng. J. Med., 1960, 263: 189; E. H. Kass, et al., "Prevention of Infection of Urinary Tract in Presence of Indwelling Catheters", J.A.M.A., 1959, 169: 1181; and E. H. Kass, et al., "Entry of Bacteria into the Urinary Tracts of Patients with Inlying Catheters", New Eng. J. Med., 1957, 256: 556.
Retrograde infection via drainage devices is in many cases attributable to the fact that conventional drainage devices are open systems which are repeatedly opened to the atmosphere and, therefore, subject to contamination during use.
Many conventional drainage devices are containers designed to be filled repeatedly with drained body fluid and emptied. For example, the evacuator described by McElhenny in U.S. Pat. No. 3,115,138 includes a capped fluid outlet. After the evacuator becomes filled it is emptied for reuse by removing the cap and expelling collected fluid via the outlet. During this operation the interior of the evacuator is exposed to the atmosphere and contamination of the evacuator may result.
Efforts have been made to reduce the contamination of drainage devices during periodic emptying. For example, U.S. Pat. Nos. 3,779,243 and 3,774,611 disclose evacuators which employ a special valve over the fluid outlet. This valve operates to close the outlet at all times except for the time when fluid is actually being purged from the evacuator. Such evacuators may succeed in reducing the contamination brought on by purging, but they are not true closed systems. Because these evacuators are periodically opened for purging, it is still possible for them to become contaminated and a source of infection.
One object of the present invention is to provide improved drainage devices and methods for reducing the incidence of retrograde infection due to contamination of drainage devices.
In addition to infection due to contamination of drainage devices, a second source of patient infection is contamination of devices for introducing fluid into the body. For example, in peritoneal dialysis large volumes of a dialysate are introduced into and then drained from the peritoneal cavity daily. One conventional approach to this mode of treatment is to use a permanent indwelling catheter and then simply to connect the catheter successively to a series of containers, each of which contains a portion of the total fluid introduced into the body.
In this approach the indwelling catheter is connected to and then disconnected from a number of containers in sequence. The same connection point on the catheter is repeatedly brought into contact with the dialysate and then exposed to the atmosphere. This repeated wetting and exposure to atmosphere is believed to contribute to contamination of the catheter and associated infection. In much the same way, devices for irrigating body cavities such as the bladder may become infected as they are connected to and then disconnected from a number of containers of irrigation fluid in succession.
Thus, a second important object of the present invention is to provide improved devices and methods for introducing fluid into human and animal subjects with reduced possibilities of contamination thereby improving sterility and reducing infection.